Suture needles have long been used to guide and draw sutures through the tissue surrounding a wound. Even today, the function of commercially available suture needles continues to be singular in nature, namely to guide and position the suture to close wounds.
Unlike hypodermic needles commonly employed to deliver fluids subcutaneously, suture needles must serve as a tool to guide and draw a suture into position along the path of a wound. Hypodermic needles employ a hollow needle and pressurizable reservoir to deliver fluids to the body. The hypodermic needle is typically hollow through its entire length with a sharp distal end for penetrating tissue and a proximal end that is hermetically sealed to a connector that may be attached to a syringe or IV tube. A syringe or IV is attached directly to the hyperdermic needle to deliver a predetermined quantity of fluid. Although this time-tested method of delivering medication to the body serves its singular purpose effectively, it is not readily adapted to serve the alternate function of closing wounds, since multiple passes of the suture needle through the tissue surrounding the wound and knotting of the suture are typically involved in the wound closure process. Consequently, the large syringe or reservoir employed with hypodermic needles may not be connected directly to the suture needle. Likewise, because suture needles are not designed to transport a fluid and are not easily connected directly to an external reservoir of fluid without severely impairing their primary function as a tool for wound closure, suture needles are not used for drug delivery. Nevertheless, a multifunctional suture needle that satisfies the traditional requirements of wound closure while simultaneously supplying a therapeutic fluid could provide many benefits associated with localized drug delivery to the wound site.
Although suture needles have been improved over the years to exhibit an exemplary combination of handling and performance properties, including but not limited to strength, stiffness, ductility, and lubricity, a number of problems are associated with the use of surgical needles. For example, the transmission of blood born pathogens occurring from accidental needle sticks poses a risk to the medical professionals conducting the wound closure procedure. Suture needles that exhibit a blunt point have been used to reduce the likelihood of an accidental needle stick. This approach relies on the fact that a high force is required to penetrate the skin with a blunt point needle. However, since most tissue is not easily penetrated with blunt point needles, the additional level of safety from accidental needle sticks is achieved only by sacrificing handling characteristics and performance of the needle. Additionally, blunt point needles in many cases will cause a higher level of tissue trauma than their sharp point counterparts. Therefore, a suture needle that affords improved resistance to the transmission of blood borne pathogens while retaining exemplary penetration performance would be beneficial to both surgeon and patient. In particular, a suture needle that emits an antiviral fluid through its tip may provide additional protection by washing blood from the tip and neutralizing virus contained therein.
A suture needle that emits an active fluid may provide benefit to the patient and surgeon in many ways. One example is associated with the need to achieve hemostasis during wound closure. Hemorrhaging often occurs through the holes formed by suture needles. Besides posing a nuisance to the surgeon, in certain surgeries such as those involving blood vessel anastomosis and certain organ surgeries, or in the cases where patients are suffering from hemophilia or consuming blood thinning medicines, hemostasis may be quite difficult to achieve. Specialized suture needles that enable the delivery of hemostatic agents or bioadsorbable sealants during wound closure may provide an opportunity to reduce bleeding through needle holes. Alternatively, vaso-constricting medicines when delivered though the suture needle may afford hemostasis at the wound site itself.
As a further example, surgical site infections are a source of many post-operative complications and deaths each year. Sutures themselves often act as a site for microbial colonization. In an attempt to reduce the rate of surgical site infections, braided sutures coated with antimicrobial agents were commercially developed. Many of these sutures have demonstrated short term efficacy in preventing the colonization of microbes in the proximity of the suture itself. However, the types of sutures that may be effectively combined with antimicrobial agents, as well as the duration and zone of efficacy are limited. Hence a number of benefits over the current antimicrobial suture technologies may be achieved with a suture needle that emits a fluid to the tissue surrounding the wound. In particular, the quantity of antimicrobial agent that may be delivered from a suture needle can be much greater than the quantity of active agent that may be incorporated into commercially available antimicrobial sutures. A larger quantity of antimicrobial agent may extend the duration of efficacy as well as extend the zone over which an antimicrobial effect is realized. Moreover, a combination of antimicrobial agents may be mixed in a single liquid vehicle to help combat a broader flora of microbes.